US5121380A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disc cartridge shutter
Assignee: Maxell Ltd
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Filing: 1988-07-29
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Granted: 1992-06-09
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Expires: 2008-07-29
Abstract
Abstract A disc cartridge comprising a cartridge case having head insert openings and encasing a disc-type recording medium rotatably mounted therein and a shutter for opening and closing the head insert openings mounted on the cartridge case, the shutter being molded from a synthetic resin material having a water absorbability of not more than 0.05% by weight and a maximum bending strength of not less than 500 kg/cm 2 . The resulting shutter has a good resistance to deformation by an external force during working, handling and preservation. The shutter also comprises spherical crystals.
Inventors
- 👤 Minoru Fujita
- 👤 Yoshitake Kato
- 👤 Kazuya Fukunaga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:45
CPC Classifications
G; G11; G11B; G11B23/00; G11B23/02; G11B23/03; G11B23/0301; G11B23/0308
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
103 words
A disc cartridge which comprises a cartridge case having head insert openings, said cartridge case encasing a disc-type recording medium rotatably supported therein, and a shutter for opening and closing said head insertion openings mounted on said cartridge case, said shutter, having improved mechanical strength and surface hardness, being molded from a synthetic resin material selected from at least one member of the group consisting of a crystalline polypropylene homopolymer, a crystalline polypropylene copolymer, or a crystallizable resin containing a crystal nucleating agent, said synthetic resin material having a water absorbability of not more than 0.05% by weight and contains small spherical crystals.
Claim 2
Dependent Claim
103 words
A disc cartridge which comprises a cartridge case having head insert openings, said cartridge case encasing a disc-type recording medium rotatably supported therein, and a shutter for opening and closing said head insertion openings mounted on said cartridge case, said shutter, having improved mechanical strength and surface hardness, being molded from a synthetic resin material selected from at least one member of the group consisting of a crystalline polypropylene homopolymer, a crystalline polypropylene copolymer, or a crystallizable resin containing a crystal nucleating agent, said synthetic resin material having a water absorbability of not more than 0.05% by weight and contains small spherical crystals.
Claim 3
Dependent Claim
35 words
A disc cartridge according to claim 1, wherein said synthetic resin material is a crystallizable polyolefin resin containing a crystal nucleating agent, such that said molded shutter contains a large number of small spherical crystals.
Claim 4
Dependent Claim
14 words
A disc cartridge according to claim 2, wherein said crystallizable polyolefin resin is polypropylene.
Claim 5
Dependent Claim
22 words
A disc cartridge according to claim 2, wherein said crystallizable polyolefin resin has a melt flow rate of not less than 20.
Claim 6
Dependent Claim
21 words
A disc cartridge according to claim 1, wherein said shutter has a U-shaped cross-section including side members and a connecting member.
Claim 7
Dependent Claim
64 words
A disc cartridge according to claim 5, wherein a shutter guide groove is provided on a front side edge of said cartridge case in parallel therewith, and an engaging lug, bent inwardly, extends from at least one of said shutter side members towards an opposite side, said engaging lug engaging with said guide groove, thereby allowing said shutter to move along said guide groove.
Claim 8
Dependent Claim
71 words
A disc cartridge according to claim 5, wherein an engaging lug is projected from an inside surface of said shutter connecting member, an engaging member for engaging with said engaging lug of said shutter is formed on an inside surface at a front side edge of said cartridge case, and said engaging lug of said shutter engages with said engaging member, thereby allowing said shutter to move along said engaging member.
Claim 9
Dependent Claim
68 words
A shutter for a disc cartridge which encases a disc-type recording medium, said shutter comprising a molded synthetic resin material selected from at least one member of the group consisting of a crystalline polypropylene homopolymer, a crystalline polypropylene copolymer, or a crystalline resin containing a crystal nucleating agent, said synthetic resin material having a water absorbability of not more than 0.05% by weight and contains small spherical crystals.
Claim 10
Dependent Claim
68 words
A shutter for a disc cartridge which encases a disc-type recording medium, said shutter comprising a molded synthetic resin material selected from at least one member of the group consisting of a crystalline polypropylene homopolymer, a crystalline polypropylene copolymer, or a crystalline resin containing a crystal nucleating agent, said synthetic resin material having a water absorbability of not more than 0.05% by weight and contains small spherical crystals.
Claim 11
Dependent Claim
33 words
The shutter of claim 8, wherein said synthetic resin material is a crystallizable polyolefin resin containing a crystal nucleating agent, such that said molded shutter contains a large number of small spherical crystals.
Claim 12
Dependent Claim
12 words
The shutter of claim 9, wherein said crystallizable polyolefin resin in polypropylene.
Claim 13
Dependent Claim
19 words
The shutter of claim 8, wherein said crystallizable resin has a melt flow rate of not less than 20.
Claim 14
Dependent Claim
33 words
The shutter of claim 8, wherein said synthetic resin material is a crystallizable polypropylene homopolymer containing a crystal nucleating agent, such that said molded shutter contains a large number of small spherical crystals.
Claim 15
Dependent Claim
46 words
The shutter of claim 8, further including a hydroxy-4-alkylbenzophenone represented by the formula: ##STR2## wherein R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, in combination with said synthetic resin material whereby resistance to deterioration by said shutter is enhanced.
Claim 16
Dependent Claim
93 words
A disc cartridge which comprises a cartridge case having head insert openings, said cartridge case encasing a disc-type recording medium rotatably supported therein, and a shutter for opening and closing said head insertion openings mounted on said cartridge case, said shutter, having improved mechanical strength and surface hardness, being molded from a synthetic resin material comprising a crystallizable polyolefin resin containing a crystal nucleating agent such that said molded shutter contains a large number of small spherical crystals, said synthetic resin material having a water absorbability of not more than 0.05% by weight.
Claim 17
Dependent Claim
93 words
A disc cartridge which comprises a cartridge case having head insert openings, said cartridge case encasing a disc-type recording medium rotatably supported therein, and a shutter for opening and closing said head insertion openings mounted on said cartridge case, said shutter, having improved mechanical strength and surface hardness, being molded from a synthetic resin material comprising a crystallizable polyolefin resin containing a crystal nucleating agent such that said molded shutter contains a large number of small spherical crystals, said synthetic resin material having a water absorbability of not more than 0.05% by weight.
Claim 18
Dependent Claim
14 words
The disc cartridge according to claim 14, wherein said crystallizable polyolefin resin is polypropylene.
Claim 19
Dependent Claim
66 words
A shutter for a disc cartridge which encases a disc-type recording medium, said shutter comprising a molded synthetic resin material having a water absorbability of not more than 0.05% by weight and improved mechanical strength and surface hardness, said synthetic resin consisting essentially of a crystallizable polyolefin resin containing a crystal nucleating agent, such that said molded shutter contains a large number of smaller spherical crystals.
Claim 20
Dependent Claim
66 words
A shutter for a disc cartridge which encases a disc-type recording medium, said shutter comprising a molded synthetic resin material having a water absorbability of not more than 0.05% by weight and improved mechanical strength and surface hardness, said synthetic resin consisting essentially of a crystallizable polyolefin resin containing a crystal nucleating agent, such that said molded shutter contains a large number of smaller spherical crystals.
Claim 21
Dependent Claim
13 words
The shutter according to claim 16, wherein said crystallizable polyolefin resin is polypropylene.
Claim 22
Dependent Claim
36 words
The shutter of claim 18, further including a hydroxy-4-alkylbenzophenone represented by the formula: ##STR3## wherein R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, whereby resistance to deterioration is enhanced.
Claim 23
Dependent Claim
47 words
The shutter of claim 18, said hydroxy-4-alkylbenzophenone being selected from at least one member of the group consisting of 2-hydroxy-4-octoxybenzophenone wherein R is C 8 H 17 , 2-hydroxy-4-dodecyloxybenzophenone wherein R is C 12 H 25 , and 2-hydroxy-4-octadecyloxybenzophenone wherein R is C 18 H 27 .
Claim 24
Dependent Claim
34 words
The shutter of claim 18, wherein said hydroxy-4-alkylbenzophenone is present in an amount of from about 0.1 to 8 parts by weight per 100 parts by weight of said crystallizable polyolefin resin and filler.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-09 | 1995-12-09 | 1996-06-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-09 | 1999-12-09 | 2000-06-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-09 | 2003-12-09 | 2004-06-09 | $7700.00 | Window Closed / Lapsed |